Electropneumatic brake



Feb. 25, J. F. CRN@ ELECTROPNEUMATIC BRAKE Filed Feb, 28, 1953 INVENTOR. t JOHN F'. CRA/G- ATTORNEY.

Patented Feb. 25, 1936 UNITED STATES PATENT GFFICE ELECTROPNEUMATIC BRAKE Application February 28, 1933, Serial No. 658,924

13 Claims.

This invention relates to safety car control equipments and has for its principal object to provide an improved electro-pneumatic safety car control equipment.

In the accompanying drawing: Fig. l is a diagrammatic view, mainly in section, of a foot controlled safety car control equipment embodying my invention; and Fig. 2 is an enlarged sectional view of the foot controlled combined brake switch and safety control device shown in section at the left hand side of Fig. 1.

As shown in Fig. 1, the safety car control equipment is of the type adapted to be controlled from either end of the car and may comprise, at each end of the car, a foot controlled combined brake switch and safety control device I, a door controlling switch device 2, a door operating engine 3, and a door engine magnet valve device 4. The equipment may also comprise a brake control valve device 5, a variable load device 6, a double check valve device l, a check valve device 8, a cut-off valve device 9, a brake cylinder I0, and a main reservoir II. v

Each of the foot controlled combined brake switch and safety control devices I may comprise a casing I2, in which is slidably mounted a plunger I3 which carries on the inner end thereof a contact switch I4 which is adapted to connect the insulated contacts I5 and I6 carried by the casing.

The contact I6 in the combined brake switch and safety control device I at the left hand end of the car is connected by a Wire |29 to a wire I I5 which is, in turn, connected to a movable contact |02 of the variable load device 6, which will be described hereinafter, and the contact I5 is connected by a wire |30 to the contact I6 in the combined brake switch and safety control device I at the right hand end of the car. The contact I6 in the-latter device is connected by a wire I3I to a wire 42 leading to the brake controlling magnet valve device 43, and since the contact switch I4 in said latter device bridges the contacts I5 and I6, as will be evident from the detailed description hereinafter, it will be seen that the circuit is complete from the contact I5 in the combined brake switch and safety control device I at the left hand end of the car to the brake controlling magnet valve device 43.

The casing I2 has a chamber I'I in constant communication with the main reservoir II through the pipe I9, and a chamber I8 constantly connected to the safety control pipe 20. A valve 2| contained in the chamber I l is adapted to seat on a seat rib 22 provided in the casing for closing off communication from the chamber I'I to the chamber I 8, said valve being subject to the pressure of a coil spring 23 interposed between and engaging the valve and a cap nut 24, which has screw-threaded connection with the casing I2 for closing the open end of chamber I'I. A exible diaphragm 25 mounted in the casing I2 is adapted to engage a seat rib 26 provided in the casing for closing off communication from the chamber I8 to a chamber 27 inv 5 communication with the atmosphere through a passage 28, the diaphragm valve being resiliently pressed to its seat through the medium of a coil spring 29 interposed between and engaging the diaphragm valve and the Contact switch I4, saidl() spring also acting to urge said contact switch to a position where it bridges the contacts I5 and I6.

Preferably carried by the diaphragm valve 25, centrally thereof and extending through the .15 chamber I8, is a stem 3|! which engages the valve 2|. When the diaphragm valve is seated, closing communication from the chamber I8 to the atmospheric chamber 2l, the valve 2| will be maintained away from its seat by the stem 3020 thereby opening the chamber II to the chamber I 8. Also, when the diaphragm valve 25 is unseated, opening the chamber I8 to the atmospheric chamber 2l, the valve 2| will be held seated by the spring 23, thereby closing comuni- 25 cation from chamber I'I to the chamber I 8.

To provide for manual control of the contact switch I4, the diaphragm valve 25 and the valve 2|, a foot pedal 3| is provided which has pivotally mounted thereon a plunger 32 which is adapted to be slidably and removably positioned in the casing I2 of each combined brake switch and safety control device I, and when the plunger 32 is positioned in the casing, it engages the end of the plunger I3. 35

Pivotally mounted, by means of a pin 33, on a bracket 34 provided on the casing I2 is an arm 36 which carries at its free end an insulated contact 31, said contact being adapted, when the arm 36 is rotated in a clockwise direction, to con-l 40 neet contacts associated with a variable resistance unit 38 to a contact 4|, the variable resistance unit being connected by the wire 39 to a contact 200 in the controller reverser 4|! and the contact 4| being connected by the wire 42 to the brake con- 45 trolling magnet valve device 43, which will be described hereinafter, so as to vary the resistance in the circuit to said magnet.

The contact 37 is also adapted in one position of the arm 36 to connect a contact 2.2 3 of the variable 50 resistance unit 38 with the contact 4I and with a contact 26|, which is connected by a wire 45 to a contact 2|6 in the door controlling switch device 2, which will be described hereinafter.

The end of the arm 36 opposite the end carry- 55 ing the contact 3l is pivotally connected, by means of a pin 202, to an arm 46 which is adapted to be engaged by the forward end of the foot pedal 3|, so that when said pedal is depressed, the consequent downward movement of the arm 46 will G0 cause the arm 36 to be rotated in a clockwise dif rection, the arm 36 being normally'maintained in' release position, as shown in the drawing, by

Vthe spring 41, which is secured at one end to the arm 36 Vand at the other end to the bracket 34. The arm 46Ais slidably supported and guided Within an opening 263 provided in a lug 204 mounted on the casing I2. Y

The brake control valvemdevicej comprises a relay valve device, anv emergency valve device and a magnet valve device responsive to variations in Y the' current supply thereto Yfor controlling the operation of the relay'valvedevice.

Y The relay valve device comprises a piston 48 having, Vat one side, a chamber 49 and, at the otherside, a chamber 56 connected by a pipe |42 to thebrake-cylinder Il) and containing a release fslide; valve 5| adapted to be operated byvsaid piston,V .Said relayy valve device also comprises a uidpressure supply valve 52V containedin Vvalve `Vchamber 53 and adapted to be operated by the Y .stem 54 of the piston 48, said valve chamberV being vconnected byra pipe |43 tothe main reservoir II.V

The emergency valve device comprises a piston 55 contained ina piston chamber V56 whichv is .connected to pipe'5'|which pipe is normally connected'to the 'safety control pipe 2D, as will hereinafter be described.V The .emergency valvede-Y vice Valso comprises a slide Vvalve 63 contained in a valve chamber 64 and adapted to be operated by the piston 55. I

l i, The magnet valvedevice 43 for controlling theY supply of iuidV under pressureto andthe release Vfrom the piston chamber 49 for controlling the operation of the relayvalvedevice may comprise amagnet co-il 65 having one terminal connected to 'the wire 42 and the otherv terminal to ground vand having a solenoid core 66.

Said device also comprises a flexible diaphragm 61, Yand carried by the diaphragm6'i' Vis a member 69 having a ball-shaped end which engages a plate 'I0 in a corresponding recess, one end ofY the. plate engaging thestem of a pilot supply .valve 1I, which is subject to the pressure of. a coil spring 12 tending to seatsaid valve,and the other end of said plate-'engaging the stem of a pilot release valve 73, which is subject toI the pressurepfacoil vspring 14 tendingto unseat said valve. Interposed between the diaphragm 6l andthesolenoid core 66 is a coil spring 66Which is adapted to be compressed by the movement ofthe solenoid core 66, the movement of thecore being proportioned to thelextent that the coil 65 is energized.

According to one feature of my invention, the vbraking power is varied accordingV to the load on the car by Vproviding means controlled bythe load onfthe car for Varying the current supply to Hso . the Vmagnetcoil 65, and for thispurpose a load controlled apparatus Vis employed comprising a strut cylinderil, a Ylocking mechanism 'I6 anda magnet valve device 11.

Pivotally mounted Yon the capk205 of the strut cylinder. 'I5 isacrank arm member having the crank arms 'I8 and 19, Carried preferably by thearm '|8 is an arm I|l| having mounted thereon a contactmember'I02, a section of insulating materialI'IlJ `being interposed in the arm IDI to insulate the contact member. |62 from the arm IUI. Thecontact member |02 wis permanently connected bythe wire |03 toa contact 266 in the controller reverser 40. When thearmV IIJI is rotated, the contact member |02 engagescontacts associated with a variable resistance unit I 24,

one terminalplf which is connected to a current supply wire |46 which is supplied withcurrent a clockwise movement,V to engage a member mounted on the caritrucks (not shown).

,. shown) from the trolley wire |41, so that the resistance in the current supply circuit is varied, and thereby the current'supplied to the magnet coil 65, by Y' operation of the contact member 31.

The arm. 'I9 is connected by a link 80 to a` ratchet bar 8| slidably mounted in the casing of the locking mechanism 16, and aV pawl 82 is adapted tol engageV the teeth of the ratchet bar, the pawl being operatively connected toa piston 83,'which piston is subject on one side to the Vpressure of Ya spring 84 and on the opposite side to uid under pressure as suppliedto Va'chamber 85 through a passage 86V/ from the chamber 81V of the magnet valve device 'I'I. Y

The magnet Vvalve device 'Il may comprise a magnet 88 and a double beatYV valve 89,. AThe coil of the magnet 88 is connected by a wire |28 toa contact 20'! in the door controlling switch 4de-V Y vice 2.

2. 'Ihestrut cylinder V'I5 containsapiston 9D havi" ing a stern 9| which is pivotally connected to a lever 92.r One end of the lever 92 is pivotally connected to a rodV 93, the other'end'of said rod be;

ing pivotally Yconnectedto the arm 18; The other YendY of the lever 92 is pivotally connectedto a Yrod 94 whichis operatively connected to an arm 95 of a bell crank member which is pivotally mounted on a bracket 96. Y The bracketV 96 is secured to lsomeportion of the car body. The other arm 97 of the'bell crank member is adapted, upon 98 :The fluidpressure kon piston 96. is controlled by a double beat valve 9S and the'o'peration of the double beat valve'is controlled-by a piston |00, one side oi which is in constant communication with the piston chamber 85.

The main reservoir I'IV orrother source of fluid under pressure is connected bythe pipes |43 and |04 to a passage |05 leading Ytothe dOuble ,beat valve SSfand through a branchV passage |06Yto the doublebeat valve 89.

The opening and closing of the car doorsis ao Y I controlled by the door enginej3 ateach end of t the car, which Ycomprises apiston cylinderV 'clon-i1A Vtaining` the` pistcns lll'l'and |68Y connectedto-V V gether bya lstern |09 carryingta rack barY I'Ill.Y Y, The teeth ofthe rack bar engage the teeth oi 'a2 4`gear segment `V| |I and saidv segment is`provide'd with alever arm I I2, to which isroperatively coni nected a rod II3 forroperating the car doorinot Mountedon Vthe' rod"||3'.;is a switchV member 4 which, atlthe left 'hand end of the car is adapted to connecta'contat 2628'toa con.;

the wire III to the wire |63.Y

The supply of fluid under pressure to and the release of iuid under pressure from the pistons |61 and |68 is controlled by a rotary valve YI I6 and said valve is operable by a piston having a stem IIlV which is connected to the valve by an arm or lever IIS.

l 2 kWhen the rotary valve I I6 is held bythe armY I9 in the door closing Vpositioniasl shown in the.

drawing, .pipe |34, Whieli is normallyconnected described, is connected by a cavityf|6f| in said to the safety control pipe, as will be hereinafter Y rotary valve `to the pipe |55 leading -to the piston |01 and the pipe |5| leading to the piston |39 is connected by a cavity |55 to the atmospheric `exhaust port |55. When the rotary valve H5 is rotated in an anti-clockwise. direction by the arm H9 to the door opening position, the pipe |34 is connected by the cavity |55 to the pipe |5| and the pipe |58 is connected to the atmospheric eX- haust port |56.

A spring 25 urges the piston in one direction and the `supply of fluid under pressure to and the release of fluid under pressure from the opposite side of the piston is controlled by the door engine magnet valve device l associated with each door engine and comprising a magnet |2| and a double beat valve |22 adapted to be operated by said magnet. The magnet |2| at the left hand end of the car is connected by a wire |23 to a contact 2 l2 in the door controlling switch device 2. The magnet |2| at the right hand end of the car is connected to a contact 2|3 in the door controlling switch device 2 at the left hand end of the car by means of the wires |26 and |21.

The door controlling switch device 2 at each end of the car is shown in diagrammatic development form and may comprise a movable drum |24 carrying the insulated contacts |25, 2M and 2| 5, which are adapted to engage and connect with a plurality of stationary contacts 2| 5, 2|2, 2| 3 and 20?, which are connected to the wires 45, |23, |2'l and l28, respectively, for the purpose of controlling the car doors and the operation of the variable load device. 5.

The double check valve device l is interposed in the piping between the safety control pipe 2G and pipe 5i, and may comprise a casing containing a double check vaive |32, the chamber 52 at one side of said check valve and the chamber |33 at the other side. being connected to the respective safety control pipe 23 leading to the combined brake switch and brake controlling devi es at the opposite ends of the car` The double check valve |32 is slidable in the casing, and in its right hand position, as shown in the drawing, establishes communication between the safety control pipe 23 leading to the left hand end of the car and the pipe 6|, and closes 01T communication from the safety control pipe 223 leading to the right hand end of the car and the pipe 6|.

The cut-off valve device 9 controls communication from pipe 5| and the safety control pipe 23 to pipe 59 and may comprise a casing having a passage 2 il connected to pipe 6| and a passage 2|8 connected to pipe 59. vMounted in the casing is a diaphragm valve 5B which is adapted to be moved so as to seat on a seat rib |16 formed in the casing and close off communication between the passages 2H and 2|8. Also mounted in the casing is a iiexible diaphragm which, through the medium of the follower members |18 and |23, is adapted to control the operation of valve Sil.

Y The chamber |83 at one side of the diaphragm lll is constantly connected through the pipes 125 and M2 to the brake cylinder l0.

In operation, the main reservoir being maintained charged with iluid under pressure in the usual manner, fluid under pressure is supplied therefrom through pipes 53 and iS to the chamber |'l in the combined brake switch and safety control device at each end of the car and to the supply valve chamber' 53 of the brake control valve device 5, and thence from the latter cham- 'ber through a passage |52 to the pilot supply valve chamber |55. Fluid supplied to the passage |52 also flows through a passage |53 to the emergency slide valve chamber 64.

Assuming that the car is being operated from the left hand end of the car, and that the right hand end is the non-operating end, at which the pedal has been removed, the spring 23 of the device at the non-operating end maintains the Valve 2| seated on the seat rib 22 and said spring, acting through the medium of the valve 2| and the stem 30 maintains the diaphragm valve 25 away from its seat rib 26. Due to the fact that the diaphragm valve is thus held unseated, chamber |33 in the double check valve device is maintained connected to the atmosphere through the pipe 20 on the non-operating end of the car,`

chamber I8, past the unseated diaphragm valve 25, chamber 21 and the atmospheric passage 2S, for a purpose which will be explained hereinafter. The valve 2| being held seated, communication is cut off from the supply chamber Il to the vented chamber |8.

Further, the spring 29 in the combined bral-:e switch and safety control device at the nonoperating end of the car maintains the contact switch |l| in the closed position, wherein said switch bridges the contacts I5 and |6, for a purpose which will be apparent from the description hereinafter. Also, the spring lll at the non-operating end maintains the contact 31 in the position shown in Fig. l, in which the circuit ously mentioned, ows into the safety control pipe 20 by Way of the unseated valve 2| and chamber 8.

Fluid thus supplied to the pipe 20 flows into chamber 62 of the double check valve device l,

causing the check valve |32 to move to its right hand seated position, if it should not already be in that position, due to the fact that the chamber |33 in said device is vented through the combined brake switch and safety control device at the non-operating end of the car, as explained hereinbefore. From chamber 62, iiuid iiows to the emergency piston chamber 56 of the brake control valve device 5 through pipe 6|, passage 2H, chamber |8| and passage 2|8 in the cut-off valve device, the diaphragm valve 5D being unseated since the chamber |80 is Vented through the brake cylinder pipe |42, as hereinbefore described, and thence through pipes 59, 58 and 5l.

Fluid under pressure supplied to pipe 6|, as above described, may also iiow to pipe 59 by way of the pipe |55, the check valve device 8 and the pipe |56, but this is of no significance at this time.

Because the foot pedal 3| at the operating end of the car is held depressed, as explained, the contact switch I4 is heid away from the contacts |5 and I6, so that a safety control circuit is held open, the circuit being traced as follows, beginning at the current supply wire H5: wire |29. contact l5, contact switch i4, contact I5, wire |39, and contact l5, contact switch I4 and contact i6 in the combined brake switch and safety control device at the non-operating end of the car, and the wires |3| and 42 leading to the brake controlling magnet valve device 43.

.Assuming that the pedal 3|,- while being heldV depressed is also maintained in the position. shown at the left, then the arm 36 will be held in the normal, or release position, shown in Fig. l, by the spring 41, in which position the contact 31 is not inV engagement with the Contact 4| and the contacts associated with the variable resistance unit 38, so that, with the controller Vreverser 46 at the operating end of the car inthe forward position, the circuit is open, which includes the contact member 62, wire |63, the 'contacts 266, V22|) passage 6 v supplyvalve 1| and the spring andr20 in the controller reverser 46,'wire 39, the variable resistance unit 38, the contact 4|, wire 42 and the brake controlling magnet valve de-k vice 3.

, Inasmuch the circuit of the magnet valve device 43 is open, due to the position of the con` tact 31 andthe position of the contact switch i4 at the operating end of the car, the Vmagnet valve device 43 remains deenergized. The solenoid core V66'Y therefore remains in the position shown in Fig. 1, and the springl not being under ccmpressiong. the diaphragm 61 remains flexed 11p- Vvvardly, permitting the spring 12 to seat the pilot 14 to unseat the pilot release valve 13.

VWith the pilot release val'.'e'13,V unseated as described, the relay piston chamber 49 in the brake vcontrol valve device 5 connected to the ,atmosphereV through the passages |15 and |51, chambel` |58, past the unseated pilot release valve 13, chamber 14, passage |59, cavity |60 in the emergency slide valve 63 and Vthe atmospheric The brakecylinder is open tothe atmosphere through pipe |52, valve chamber 50, past the release valve and then through the atmospheric passage |62. j

It Ywill be ncted that with the contact 31 of the combined'brake switch and safety control device lat the operating end of the car in the Y' connected by wire 45 to contact 2|6 in, the door .controlling switchV device 2. VThe door Ycontrol-gfV ling switch devicewill normally becarried in the door'closing position, in which'the circuit is also 1 open at the contacts 2|,6,2|2,and 2|3Y from the VWireY 45 to the Wires |23 and |21 leading vto the door engine magnet valve devices 2| Yat they operating and non-operating ends of the car, re ,spectively With the circuitV to the magnet valve devices. |2|V open, said devices remain deenergized AVand the double beat valve |22 remains in a po- Yfsition wherein the passage |63 leading to piston ||1 isY V.connected to Vthe atmospheric exhaust portY |64. VrIfhe piston ||1 being'V subject to at-` mospheric pressure, the spring |26 holds piston ||1 in its right hand position and the valve V| I6' inthe position in which it is shown in the drawing, in which a cavity |65 connects pipe |5|,

f YVleading to the door opening piston |68, with an atmospheric'exhaust port |66. The door closing piston |81 is subject to fluid under pressure supplied through the pipe 58, pipes |48 and |34, the

lever Y| 2 operates through rod. ||3 to hold 4cavity, |61 Vin the valve |16 and pipel.

The piston |61 at jeach end of the car being Y,thus subject to fluid pressure while piston |03 is subject to atmospheric pressure, the pistonwill beheld inthe door closed position, in which the the

car door (not shown?- closed. VY.When the cardoorV is closed, the switch'memberV 4 is positioned Vby lever ||3 so that said member does not closeY the circuit from the wire ||5 to the Wire 42.5

When the car is running Valong the road, with all doors closed, as described,Y the circuit in.- cluding the Wire |28 leading to the magnet valve device 11 of the variable load device 6 is open at the door controlling'switch device 2 and'said magnet remains deenergized. The double beatl valve 89 Vwill then be in the position shown in Figl 1, in which communcation is open for supplying fluid under pressure from the main res'- ervoir |y to the piston chamberV 85 through pipesV |43 and |04, and passages |65 and 06, past the Y. unseated double beat valve 89, thence through the chamber 81 and passage 86, causingthe pistonY 83 to beheld Yin its left hand position so `as to maintain the'pawl 82 in engagement withthe teeth inthe ratchet bar 8|.

Fluid under pressureinV piston chamberl 85 is also supplied to piston so that the double Ybeat' valve 99 is heldin ne position shown in Fig. 1, in which the piston 9E is connected through passage |68 with the atmosphere. Springm|69- then acts to Vhold piston 9i] in its retracted poi siton, so ythat the arm 91 does not engage the member 98. Movement Yof the car truck will therefore not be transmitted to the Vmechanism in the variable load device Vil'fhilethe car is run` ning. Y

fit vis desired toV apply the brakes, the ,foot pedal 3| is rotated in an anti-clockwise direction from the position shown in Fig. 1, causing the arm 36 to be rotated in a clockwise direction intoV the applicationzone, so that the contact 31 con-V nests the contact 4|VV with the contacts or the variable resistance unit; 38, dependent upon the degree of brake application desired. Current will then besupplied to the circuit including the magnet coil 65 which varies according to the Vamount Y of resistance whichY is cut into the circuit by the positioning of the Vcontact 31.

Due to the energization of the magnet coil 65, the solenoid core 66 Willbe shifted downwardly by thermagnetic pull of said magnet coil,fthereby compressing the spring 68. Since the spring 68 Y acts on the diaphragm 6,1, said'diaphragm will be flexed downwardly by the pressure of the spring. Since the spring 12 acting on the pilot supply valve 1| is preferahlysomewhat heavier than the spring Y14 actingV on the pilotV release valve 13,V the initial movement ofthe plate 10 by the diaphragm 51 operates, with the stem of the valve 1| acting `as a fulcrum, to move the' valve 13 downwardly to its seat, closingA off communication from theY chamber |58 to-the atmosphere through passage |59, cavity |60 inthe emergency slide Vvalve 63 and the passage IGI.

Further movement of the diaphragm 51 then rocks the plate 10, with the stem of the valve 13 acting as a fulcrum, so as to unseat the valve V1|. Fluid under pressure supplied fromY the main.

reservoir through the pipeV |43 to the chamber 53 flows therefrom to the relay piston chamber 49 through the passage |52, chamber |54, past the unseated valve 1|, chamber'l58 and passages |51 and |15. The piston 48 is then operated by uid pressure to first shift the release'slide valve 5|,i so as to cut'oif communication from the brake through the passage |62, and then further movement of the piston stem 54 operates ,to unseat the supplynvalve 52, so that fluid under pressure: is

` cylinder I6 to the atmosphere throughlpipe |42, chamber 55, past the release slide valve 5|, andl Y supplied from the valve chamber 53 and the main reservoir to valve chamber 50 and from thence through pipe |42 to the brake cylinder I0, thus causing the brakes to be applied by iiuid under pressure supplied to the brake cylinder. Fluid supplied to pipe |42 will also flow to chamber |80 in the cut-oli valve device 9, for a purpose which plate 10, during the upward movement of said plate, so as totilt the plate, with the stem of the pi-lot` release valve 13 acting as a fulcrum.

It will now be seen that both the pilot supply valve 1| and the pilot release valve 13 are closed or lapped andthe parts will remain in this position so long as the pressure in the piston chamber 49 corresponds with the pressure to which the spring 68. is set.

When the pressure of fluid supplied to valve chamber 50 has been increased to a degree slightly in excess of the pressure of uid supplied to the piston chamber 49, the piston 48 will be shifted so as to permit the valve 52 to seat and thus cut oft' the further supply of iiuid to the brake cylinder.

If, while the brakes are applied, it is desired to increase the braking force, the foot pedal 3| is rotated, still farther in an anti-clockwise direction,` causing the arm 35 to be rotated farther in a clockwise direction so as to cut out a greater amount of resistance of the variable resistance unit 38. In this way, the strength of current supplied to the magnet coil 65 is increased, and the coil being thus more strongly energized, the solenoid core 66 is operated to further compress the spring 68 so as to further deflect the diaphragm 6'!y downwardly and thereby again open the valve 1|. Fluid under pressure will then again be supplied to the piston chamber 49 until the pressure in said chamber and in chamber |58 is slightly in excess of the opposing pressure of the, spring 68, when the diaphragm 61- will againbe flexed upwardly, permitting the valve 1| to beclosed, in the manner hereinbefore dei scribed.

, The: increase of pressure in piston chamber 49, due to the unseating of the valve 1|, as described, will cause said piston to operate so as to cause the valve 52 to be unseated to admit a further supply of uid to the brake cylinder, as. herenbefore described.

The degree of brake cylinder pressure obtained is determined by the amount of resistance. of the variable resistance unit 38 cut out of the circuit to the magnet coil 65 by the contact 31,V the maximum pressure being obtained when the contact 31 is so positioned that all of the resistance of the variable resistance unit 38 is cut out of the circuit to the magnet coil 65, or in other words, when the contact 31 connects the contact tact 2|9 to the contactl 20|, so thatthe circuit is complete from the supply wire |03 to the contact 2|0 in the door controlling switch device 2, which circuit includes the contacts 206, 220 and 200 in the controller reverser 40, wire 39, contact 2|9, Contact 31, contact 20|, and wire 45.

With, the contact 31 in full application position, if the operator desiresV to open the front door and to maintain the rear door closed, he moves the door controlling switch device 2 to front door open position, in which the contact bridges the contacts 2|6 and 2|2. The circuit is now complete from the supply wire |03 to the door engine magnet Valve device 4, which circuit includes the contacts 20B, 220 and 200 in the controller reverser 40, wire 39, contact 2|9, contact 31, contact 20|, wire 45, contacts |25, 2|6. and 2|2', and wire |23.

The ow of current to the magnet |2| of the magnet valve device 4 at the frontend of the car energizes said magnet, causing the double beat valve |22 to be seated on the upper seat and unseated from the lower seat. The seating of valve |22 on the upper seat cuts off communication from the passage |63 to the atmospheric passage |64 and the unseatng of valve |22 from the lower seat opens the passage |63 to the pipe |48, so that uid supplied to said pipe from the charged safety control pipe, as hereinbefore described, will iow past said unseated valve and through passage |63 to the piston ||1. Said piston is moved by iiuid under pressure and the rotary valve H6 is operated to cause cavity |65 to connect pipe |34 to pipe |5| and to cause cavity |51 to connect pipe |50 to the exhaust port |65.

Fluid under pressure is then supplied to the doory opening piston |08 while the door closing piston |01 is Vented, and consequently the pistons |01 and |08 are shifted toward the left hand, causing the rod ||3 to be operated so as to effect the opening of the front doors.

The movement of the rod I3 causes the switch member ||4 to bridge the contacts 209 and 208, thereby closing the circuit from the supply wire |03 to the magnet coil 65 of the brake controlling magnet valve device 43 through the wire H5, contact 209, switch member ||4, contact 208 and wire 42, for a purpose which will now be described.

If the operator should attempt to release the brakes by permitting the contact 31 to move in an anti-clockwise direction toward release position, asY will be described hereinafter, before the door has started to close, he cannot do so because, while the circuit to the magnet coil 65 of the brake controlling magnet valve device 43 will be opened by the disconnection of the contact 219 from the contact 20| as the contact 31 is moved out of full application position, current will still be supplied from the wire ||5 through the switch member ||4 to the wire 42, to maintain the brake controlling magnet valve device 43 energized.

If it is desired to open the rear door and maintain the front door closed, the operator moves the door controlling switch device 2 to rear door open position, in which the contact 2|4 bridges the contacts 2|6 and 2|3. With the contact 31 in full application position, as described, the circuit is now complete from the supply wire |03 to the magnet |2| of the door engine magnet valve device 4 at the rear end of the car, which circuit includes the contacts 206, 220 and 200 in the controller reverser 40, wire 39, contact 2|9, contact 31,y contact 20|, wire 45, contacts 2|6, 2|4

6 and A2lb in .the door controlling switch` device` 2 and Wires |21 and |28.

'Ihe flow of current to the magnet |2| at the rear end of the car energizes said magnet, causing the door operating engine 3 at the rear end of the car to be operated so as to open therear door, in a manner similar to the operation of the door operating engine 3 at the front end of the car, hereinbefore described, for opening the front door.V

The operation of the door operating engine for opening Vthe rear door also causes the switch Vmember H4 to close a. circuit from the supply Y -wire |88 to the magnet coil 85 of the brake con- Vtrolling magnet valve device 43, which circuit includes the wire Ill, contact 2li, switch member ||4, contact 2|8 andwires 22| and 42, so Vas to Y maintain the brakes applied while the rear door KUis open, as hereinbefore described in connection Ywith the operation of the door operating engine for controlling the operation of the front door.

If it is desired to open both doors, the operator moves the door controlling switch device 2 to both doors openposition, in which the door opening 4"sides of Vboth door opera-ting engines are supplied with uid under pressure and in which the door closing sides of these engines are ventedY to atmosphere, in the'manner hereinbeiore described,

Y causing the engines to operate to open both doors.

IFurther, each switch member H4 is operated to Y close a circuit to the brake controlling magnet valve device 43, as hereinbefore described.

When it is desired to close the doors, the door controlling switch device 2 is moved to "doors closed position, in which the supply of current to the magnets |2| is cut off by theopening of the circuits of the contactsZlG, 2|2 and 2|3. Each magnet i2! is thereby deenergized and the `double beat valve i 22 is operated so as to reestab- I34 is connected by the cavity |61 to the pipe 1 Ylish communication from the piston ||1 to the atmosphere through passage |63, past the unseated double beat valve |22 and the atmospheric port I 64. Spring |28 will then shift the piston ||1 to its right hand position and the valve H6 Vto the position shown in the drawing, in which the cavity |85 connects the pipe VV|5|, leading to piston |88, with theatmospheric exhaust port |86 and in which the fluid pressure supply pipe |58 leading to piston |81.

Due to the venting of iiuid from the door opening piston |88 and the supply of fluid under presl sure to the door closing piston |81, said pistons will be shifted to the'door closing position, as

shown in the drawing, elfecting the closing of the doors and the opening of the circuit from the contact 288 to the contactV 288 by the movement of the switch member l lli at the front end of the Acar and the opening of the circuit from the contact 2|| to the contact 2|8 by the movement of the switch member H4 at the rear end of the car. The opening of said circuits will lnot deenergize the brake controlling magnetvalve device 43 because said device is still energized by Athe current supplied through the combined brake Vswitch and safety control device I and the brakes Y therefore remain applied until released in the manner hereinafter described.

Itwill be seen that only after the door controlling switch device 2 has been moved to doors closed position and thereby effected operation of the door engines to close the doors and to move` theV switch member il!! at the front end of the car out of engagement with the contacts 288 and 288 and the switch member l I4 at the rear end of the car :out of engagementwiththecontacts 2|8 and 2|| can the brakes bereleased because,

as hereinbeforeV described, ,the brake *controlling* magnet valve Vdevice 43 is maintained Venergized by the closing of the circuit to said device through the switch member I I4 vuntil the'doorshave started to close. i l' When the door controlling switch'device 2 moved to a door opening position, the contactZ 8 is connected to the contact 281and with the contact 31 of the combined brake switchV and ,safetyy control device I in fullapplication position', cur` rent is permitted'to ow from the wire 45'to the;

wire |28 and from thence to the magnet 88 vo1.'v the magnet valve device 11'of the variable load Y Y is device 6, causing said magnet to be energized.

The energization of the magnet 88 then effects the movement of the double beat valve 89 so as to cut 01T communication from passage |86 to chamber 81 and thence to passage 8 6 and thereby cut oli the supply of fluid underY pressure to the piston chamber 85, and to open communication from said chamber to the atmosphere by way of passage 88 and chamber 81 and thence past the unseated valve 88.

The Venting of fluid pressure from the piston chamber 85 permits the spring 84 to shift the piston 83 outwardly,V thus releasing the pawl 82 from engagement with the teeth of'therack bar 8|, so that said bar is free to sli/de. I Y When fluid is vented from piston .chamber 85,

fluid is also vented from thepi'ston |88, so that" Y the double beat valve 88 isoperated to out ofi'- the atmospheric vent from passage |68 andv open communication from the main reservoir through passage |85 to passage |68. FluidY under presf'j Vsure is then admitted to piston 88, so as to shift' said piston outwardly, causing the arm 81 toY engage the member 88. The end of the rod 84 tate in a clockwise direction so that the rod 83 is pulled toward the right hand. This movement of the rod 93 also operates to rotate the crank arms 18 and 18 in a clockwise direction. Y

VThe rotation of the crank arm 18 causes the contact arm |8| to move toward the right handv a distance which is proportional to the increase inthe load on the car, and a corresponding amount of resistance is cut out ofthe variable resistance unit |24. Thus the current supply to the Vcombined brake switch and safety'control device is proportional to the load onrthe In other words, the greater the load onA the car, the Yless the amount of `resistance in the circuit to the combined brake switch and safety control'devicerand therefore the greater will be the current flow tothe brakevcontrol ling magnet valve device 43 in any given applif Ybrake switch cation position of I the combined and safety control device l. Y

The rotation of the crank arm 19 causes ratchet bar 3| to be moved upwardly through themedium of thelink'88. When the car has been loaded and the door controlling switch device 2 is moved to doors closed position for closing.

the doors, the circuit is broken from the wire to the wire |28 and the magnet 88 will be de-v toL energized. Dile to the deenergization of the magnet 88, the double beat valve 89 will be operated to cut oir the atmospheric vent from pistons 83 and I and to open communication for supplying fluid under pressure to said piston chambers.

The supply of fluid under pressure to piston chamber 85 causes the piston 83 to be moved towards the left hand so that the pawl 82 will engage the teeth of the ratchet bar 8| and thus lock said bar against movement, and consequently the arm IDI carrying the contact member |02 will be locked in its adjusted position.

When uid under pressure is supplied to piston chamber 85, fluid is also supplied to piston |00, so that said piston operates the double beat valve 99 to open passage |58 to the atmosphere. The piston 90 is then shifted to its retracted position, in which the arm 91 of the bell crank member is moved out of engagement with the member 98.

To completely release the brakes, lthe operator relieves the pressure of the foot on the forward end oi the foot pedal 3| so as to permit the spring 41 to rotate the arm 35 in an anticlockwise direction to release position, opening the circuit from the variable resistance unit 38 to the Contact 4| and thereby eiecting deenergization of the magnet coil 65 of the brake controlling magnet valve device 4S.

With the deenergization of the magnet coil 65, no magnetic pull is exerted on the solenoid core 66 so that the spring 68 is relieved oi compression. This release in spring pressure on diaphragm 51 causes the higher pressure in chamber |58 on the opposite side of the diaphragm to move the diaphragm upwardly, permitting the plate 19 to be tilted upwardly by the action of the spring 14. on the pilot release Valve 13, with the stem of valve 1| acting as a` fulcrum for said plate, thus permitting the pilot release valve 13 to be unseated by the spring 14.

With the pilot release valve 13 unseated, pisn ton chamber 49 is vented through passages |15 and |51, chamber |58, past the unseated valve 13, passage |59, cavity |65 in the emergency slide valve 63 and atmospheric passage I 5I. The pressure of the fluid in the release slide valve chamber 56 then causes the piston 48 to operate to its extreme left hand or release position, carrying with it the release slide valve 5|. With the release slide vaive 5| in release position, fluid under pressure from the brake cylinder ID is vented to the atmosphere through pipe |42, chamber 5G, past the release slide valve 5I and through the passage |62.

Should it be desired to eiect a graduated release of the brakes, the operator, instead of permitting the contact S1 to return fully to release position, as he does in eiecting a full release, may cause the contact 31 to stop in any desired intermediate position within the application zone. Upon the movement of the contact 31 toward release position, the amount of resistance of the variable resistance unit 38 cut into the circuit with the magnet coil 55 oi the brake controlling magnet valve device 43 is gradually increased, thus decreasing the magnetic pull of the coil on the solenoid core 66. The decrease in the magnetic pull of the coil on said core reduces the compression of the spring 58. The higher pressure in chamber |58 on the opposite side of the diaphragm 61 then causes the diaphragm to move upwardly, permitting the plate 10 to be tilted upwardly by the action of the spring 14 on the pilot release valve 13, with the stem of valve 1| acting as a iulcrum for said plate, thus permitting the pilot release valve 13 to be unseated by the spring 14.

With the pilot release valve 13 unseated, the piston chamber 49 is vented and the release slide valve 5| is thereupon moved by the piston 4B to release position, so as tc permit ow of iiuid from the brake cylinder to the atmosphere, in the manner hereinbefore described. However, when the pressure of fluid in chamber |58 has been reduced to a degree less than the pressure exerted by the spring 53, the diaphragm 61 will be moved downwardly by said spring, causing the plate 113 to tilt downwardly, with the stem of valve 1| as a iulcrum, and effect the closing of the pilot release valve 13.

With the valve 13 seated, further release of fluid from piston chamber 49 is prevented and when the pressure of the fluid in the release slide valve chamber 5G, and consequently in the brake cylinder I0, has been reduced slightly below that retained in chamber 4.9, the release slide valve 51 will be operated by the piston 48 so as to cut ofi further flow of fluid from the lbrake cylinder to the atmosphere.

Should the operator become incapacitated so that he can no longer maintain pressure on the foot pedal 3| in the combined brake switch and safety control device, an automatic application or^ the brakes will be effected. Upon the release of pressure from the foot pedal, the spring 29 moves said pedal upward through the medium of the plungers I3 and 32 and causes the contact switch I4 to bridge the contacts I5 and i6 in the combined brake switch and safety control device I at the operating end of the car, thereby closing the circuit from wire |29 to wire |30. Inasmuch as the circuit from wire |35 to wire d2, leading to the magnet valve device 43, is closed by the bridging of the contacts I5 and I6 by the Contact switch I of the combined brake switch and safety control device I at the non-operating end of the car, the closing of the circuit from wire I 29 to wire |38 by the contact switch |4 at the operating end of the car causes the circuit to be closed from the supply wire |46 to the magnet valve device 43 by way of the variable resistance unit |24, contact member |82, wires IBS, ||5 and |29, contacts I5 and I6 and contact switch I4 in the combined brake switch and safety control device at the operating end of the car, wire |39, contacts I5 and I5 and contact switch |4 in the combined brake switch and safety control device i at the non-operating end of the car, and wires I3| and 42.

With the circuit to the magnet coil 65 of the magnet valve device 43 thus closed, the solenoid core 66 is operated by the energization of the coil 55 to effect an application of the brakes in the same manner as when said coil is energized by the movement of the Contact 31 in eecting an application of brakes in the normal manner, as hereinbefore described.

Due to the pressure of the spring 29 on the diaphragm valve 2.5 being relieved when the operators foot is removed from the foot pedal 3|, fluid pressure in chamber I3, acting on the inner seated area or" the diaphragm valve, assisted by the pressure of the spring 23 acting on the diaphragm valve through the medium of the valve 2| and the stem Eli, causes said valve to be moved away from its seat rib 25, and the valve 2| will be seated by the spring 23.

lWith the diaphragm valve 25 unseated, fluid is 8- Y Vented from the einergenoa7 Distongchamber 56 in the brake control valve device 5 through the pipe 51, pipes 58 Vand 59, and passage 2I8, charnber I8| and passage 2|1 in the cut-off valveidevice' 9, pipe 6I, chamber 62'in the double check valve device 1, pipe'29, chamber I8, past the unseated diaphragm` valve 25, through chamber 21iand the atmospheric passage 28. TheY seating of valve 2| cutsioff communication from the Vchamber I1 to the ventedV chamber I8 and thereby prevents: loss of fluid supplied tochamber I1 from the main reservoir I I through pipes |431 and The emergency piston chamber 56 being vented, the pressure of the fluid inthe emergency slide valvef'chamber 94, as supplied from the main reservoir-through pipe |43, supply valve Ychamber 53 and passages V|52 and |53, causes theE emergency piston 55 to move upwardiy to emergency position, carrying with it the emer- [sages |13 and |15 to the relay valvef'piston chamber 49.

Thus, it will be seen that if, for? anyY reason, the magnet valve device 43 shouldrfail to operate, fluid under pressure supplied to the piston cham- :ber 49 through the operation of the emergency valve device will cause piston 43 to be operated,

in the manner hereinbefore described, to unseat the supply valve 52, whichiwill permit fluid underpressure to be supplied to the brake cylinder :I to eifect an emergency application of thek brakes. It Will alsc-g be seen that should the emergency valve device fail to operate for any reason and the magnet valve device 43 is operative to supply iiuid underpressure to the piston chamber 49, the piston48 willbe operated by said fluid supply valve to eiTect an application of the brakes. 'Ehud protectionW is provided against failure of Vthe brakes to apply in an emergency application in the Yevent that either the magnet vaive deviee 43 or the emergency valve device should fail to operate. n g

it will be noted that when the emergency@ slide valve 63 is moved to emergency position, the cavity |50 is moved out of registration with the passage |59, sofas to cut off communication from the passage |59 to the atmosphere, thereby insuring that in the event that the pilot release valve 13 is unseated for any reason, such as failure of the magnet Valve device .43 to operate, fluid under pressure supplied to the piston;V chamber 49 throughrthe operation ofthe emergency piston 55Y and slide valve 53 will not be Vj/ented to the atmosphere by way of passage |51, chamber |58, past the unseated pilot release valve 13, passage |59, cavity |50 and passage I 6I.,Y Further, in emergency position of thegslide valve 63, a port |14 in said slide valve registers with the passage |59, so that fluid is supplied from the emergency slide Valve chamber 54 through said port to passage I59, chamber I 58 and passage |51. Thus, when the emergency valve device operates and the magnet valve device fails to operate, the rate of build-up of uid pressure in piston chamber 49V through the passages |13 and L15 will not be delayed by the flaw of fluid from said passages into passage |51, chamber |58 and passage |59.

Fluid under pressure supplied to the pipe |42 in effecting an emergency application of the brakes flows to chamber |80 in the cut-ofil valve device 9 through the pipe |44. Since the Ychamapplicatien of the brakes, causes the venting of ber I8I below the diaphragm valve 60 is vented through the vented safety control pipe, fluid pres-` Y, sure supplied to chamber |80 will cause the dia` Y phragm |11 to ,beiflexed downwardly, causing theY munication through theV safety control pipe,- which, however, has no signicance at this time. s

The venting ofthe safety control pipe, as heref inbefore described, when effecting an emergency?.

fluid from the door closing piston |01 of the door operating engines 3 at each end of the car through pipe |50, cavity |61 in valve H5, pipes 34 and |48 andthe vented pipe 58. Inasmuch as the doer opening piston |08 is vented, .as here-'1l inbefore described, the door engine pistons are balanced, so that the car doors may be controlled manually. 's

In releasing the brakes aftengan emergency Y' application, the foot pedal 3| must be depressed 2 to the position shown at'the operating end of the W car in Fig. 1 and must be held in this position, in which the contact switch I4 is moved out of engagement with the contacts I and I6, thereby effecting deenergizaticn c-f the brake controlling g magnet valve device 43 and the consequent unseating of thepilot release valve13. In this po-V sition. also the Vdiaphragm valve is seated, so as to close off communication from the safety control pipe 20 V'to the atmospheric passage 278, 3 and valve 2| is unseated, so as to reestablish com-V munication from the fluid pressure supply pipe I9 to the pipe 2e.

Fluid supplied to pipe 20 ows therethrough to;

chamber 62 in the double check valve device 1,115; thence through pipe |55, and the check valve device 8, md thence through pipes |56, 59, 58 and; 51, to the emergency piston chamber 56. The; emergency piston and slide valve 63 are there by moved downwardly to release position= I .10'

It will here be understood that if fluid wereY not supplied from pipe 6| to pipe 59, byV way of pipe |55, the check valve device 8 and pipe |55, it would be impossible to supply fluid; to the emergency piston chamber 56 to effect a release 4 of the brakes after an emergency application because the valve 60, being seated, cuts oil communication from pipe 6| to pipe.Y 59 through the cut-off valve device 9. ,Y

With the emergency slide valse in release po- Y5 sition, cavity |69 againrrconnects passage |59 to the atmospheric passage IGI, permitting the release ofifluid from the piston chamber 49 by way ofrpassages |15 and |51, chamber |58, the

VVvalve to seat on the seat ribl1'6 and closecomunseated pilot release valve 13, passage |59, cav- 55 |44 and the vented pipe |42, which will permit 65 the valve 60 to be unseated and thereby ope communication from pipe 59 to pipe 6|. .i

When the brakes are applied in a service applig, cation, iiuid under pressure is supplied to the chamber |80'in the cut-off valve device S by ow. from the brake cylinder pipe 42 and thepipe |44.l When the pressure in chamber |80 is increased' sufiiciently to deect diaphragm |11, the dia-' phragm vave 60 will beshiftedby movement of the diaphragm |11, so that said valve Willerigage Cil the seat rib 116. Connection from passage 2| 1 to passage 218, and consequently from pipe 59 to pipe 6I, is thus cut olf, so that the operator may remove his foot from the foot pedal 3l after having effected a predetermined application of the brakes, without causing the emergency piston 55 to be operated. It Will be seen that the check valve device 8, by preventing flow of fluid from pipe 59 to pipe 6|, renders the valve 6l) operative to cut off communication between said pipes.

The removal of the operators foot :from the foot pedal 3| effects a full application of the brakes, however, because the contact switch I4 at the operating end of the car bridges the contacts yl5 and I6 and thereby closes the circuit to the brake controlling magnet valve device 43 which will operate, in the manner hereinbefore described, to eiect operation of the relay valve piston 48 to its application position.

While one illustrative embodiment of the inventio-n has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. In a safety car control equipment, the combination with a brake cylinder, a pipe normally charged with fluid under pressure, electro-responsive means operative upon energization to supply iiuid under pressure to said brake cylinder and operative upon deenergization to release fluid under pressure from said brake cylinder, and an emergency valve device operative upon a reduction in pressure in said pipe to supply fluid under pressure to the brake cylinder to eect an application of the brakes, of a combined foot valve and electric circuit controlling device controlled by the pressure of the foot of the operator and operative upon the relief of foot pressure on said foot valve device by the operator to effect energization of said electro-responsive means and to release fluid under pressure from said pipe.

2. In a safety car control equipment, the combination with a brake cylinder, a control pipe, electro-responsive means operative upon energization to sup-ply fluid under pressure to the b-rake cylinder and operative upon deenergization to release fluid under pressure from the brake cylinder, and an emergency valve device operative upon a reduction in pressure in said pipe to supply uid under pressure to the brake cylinder t`o elect van application of the brakes, of a combined foot valve and electric circuit controlling device subject to foot pressure for normally maintaining the pressure of uid in said control pipe and for maintaining open a circuit through said electro-responsive means and operative upon the relief of foot pressure for reducing the pressure of the iluid in the control pipe and for closing the circuit through said electro-responsive means.

3. Ina safety car control equipment, the combination with a brake cylinder, a pipe normally charged with fluid under pressure, electro-responsive means operative upon energization to supply fluid under pressure to the brake cylinder and operative upon deenergization to release fluid un- Vder pressure from the brake cylinder, and an emergency Valve device operative upon a reduction in pressure in said pipe to supply fluid under pressure to the brake cylinder to effect an application of the brakes, of a combined foot valve and electric circuit controlling device comprising contacts in a circuit of said electro-responsive means,

a switch lmember adapted to bridge said contacts for closing the circuit of said means for energizing said means, a valve for controlling a communication through which said pipe is adapted to be vented, and a foot pedal subject to the pressure of the foot of an operator for normally maintaining said switch member out of engagement with said contacts and for normally preventing said valve from operating to open said communication.

4. In a safety car control equipment, the combination with a brake cylinder, a pipe normally charged with iluid under pressure, electro-responsive means operative according to variations in the flow of electric current thereto for varying the pressure in the brake cylinder, and an emergency valve device operative upon a reduction in pressure in said pipe to supply lluid to the brake cylinder to eiect an application of the brakes, of a combined foot valve and electric circuit controlling device comprising contacts in a circuit of said electro-responsive means, a switch member adapted to bridge said contacts for closing the circuit of said means for energizing said means to effect a predetermined application, a valve for controlling a communication through which said pipe is adapted to be vented, a contact switch adapted to control the circuit of said electro-responsive means for effecting a service application of the brakes, and a graduated application and graduated release of the brakes and a complete release of the brakes, and a foot pedal for controlling the operation of said contact switch and subject to the pressure of the foot of an operator for normally maintaining said switch member out of engagement with said contacts and for normally preventing said valve from operating to open said communication.

5. In a safety car control equipment, the cornbination with a brake cylinder, a pipe normally charged with fluid under pressure, electro-responsive means operative upon energization to supply fluid under pressure to the brake cylinder and operative upon deenergization to release fluid under pressure from the brake cylinder, and an emergency valve device operative upon a reduction in pressure in said pipe to supply fluid under pressure to the brake cylinder to effect an application of the brakes, of a combined foot valve and electric circuit controlling device comprising contacts in a circuit of said electro-responsive means, a switch member adapted to bridge said contacts for closing the circuit of said means for energizing said means, a valve for controlling a communication through which said pipe is adapted to be vented, a plunger, and a pedal pivotally mounted on said plunger and adapted upon a rocking motion to control the operation of said contact switch, said plunger being operative when depressed by the pressure of the operatorsfoot on the pedal to maintain said switch member out of engagement with said contacts and to prevent said valve from operating to open said communication.

6. In an electro-pneumatic brake, the combination with a brake cylinder and electro-responsive means operative according to variations in the flow of electric current thereto for varying the pressure in the brake cylinder, of electroresponsive means for controlling the operation of a car door and operative upon energization to effeet the opening of said door, and a contact switch adapted to be moved through an application zone for varying the flow of current to the first mentioned electro-responsive means and adapted only in full application position to close Y a circuit throughV the second mentioned electroresponsive means.

7.'In an electro-pneumatic brake,"the combi` nation with a brake cylinder and electro-responsive means operative accordingV to variations in Y of a cardoor and operative upon energization to effect the opening'of said door, and a Contact switch adapted to be moved through an application Zone for varying'the'flow of current to the first mentioned electro-'responsive means and adapted when moved to a predetermined position Within the application Zone to close a circuit through the second mentioned electro-responsive means. Y Y

8. In a safety car control equipment, the combination with a brake cylinder, a safety control pipe and an emergencyV valve device operative upon a reduction in the pressure in said pipe to supply fluid under pressure tothe brake cylinder to eifect an application of the brakes, of a door engine having a door opening anda door closing position, means Yfor effecting the movement of Vsaid door engine inY one direction to a dooropen-Y ing position and in another direction to a door closing position and comprising a piston operated by fluid under pressure for effecting the movement of the door engine in one direction and op-` erative upon the relief of fluid under pressure for effecting the movement of said engine in the opposite direction, and manually controlled electroresponsive means operative upon energization to supply fluid under pressure from said safety control pipeto said piston and operative upon, deenergization to vent iluid under pressure from Y said piston. Y

9. In a safety car control equipment, the combination With a brake cylinder, manually con- Vtrolled'means for effecting the supply of fluid Y der and operative upon an increase in pressure in said pipe to cooperate with said means to effect'a'release of fluid under pressure from the brake cylinden' a manually operated valve device for supplying fluid under pressure to and. releasing fluid under pressure from said pipe, 'valve means controlled by brake cylinder pressure Vfor controlling communication from said valve device to said emergency valve device andV operated upon a predetermined increase in brake cylinder pressure for closing said communication, and a one-Way communicationY by-passing said Vvalve means for supplying fluid under pressure from said valve device to said emergency valve device. Y Y

10. In a safety car control equipment, in combination with arbrake cylinder, electroresponsive means operative accor-ding toY variations in the ilow of'electric current-thereto for varying the pressure of fluid supplied to said brake cylinder, a plurality of circuits for supplying current to Vsaid electroresponsive means, means associated with a car doorV fior controlling one of said circuits, said circuit being completed on movement of the car door to the open position, a member for controlling another ofsaid circuits and normally biased to a position to complete said circuit, and movable responsive to manual pressure of an operatorV to a position to interrupt said cir-,-

cuit, and a manually operated electric. circuit bination With'a brake cylinder, electroresponsive` means operative according to Variations in the flovvV of electric current thereto ,for varying the pressure of fluid supplied to said brake cylinder,

a plurality of circuits for supplying currentgto said electroresponsive means, means associated With a car door for'controlling one of said circuits, said circuit being completed Von, movement of the car door to the open position, a member for controlling another of said circuits and no1'- mally biased to a position to complete said circuit, and movable responsive to manual pressure of an operator to a position to V,interrupt said circuit, and a manually operatedlelectric circuit' controlling device for controllinganother of said circuits for Varying the flow of current to the electroresponsive means to varylthe pressure of the fluid in the brake cylindenand means asso# ciated Withsaid last named circuit for regulating the amount of current supplied to said electrof responsive means according to the loadV on theV car.

12. In a safety car'control equipment, in combination with abrake cylinder, electroresponsive means -operative according to variations in the flow Yof electric current thereto for varying the;

pressure of fluid supplied to said brake cylinder, a plurality of circuits for supplying current to said electroresponsive means, a-member for con-V trolling one of said circuits and normally biased Y to a position to complete said circuit, and mov.-r

able responsive to manual pressure of an operator to a position to interrupt said circuit, a manuallyV operated electric circuit controlling device for controlling another of said circuits for varying the iloW of current tothe electroresponsive meansY to vary the pressure of the fluid in the brake cylinder, common means to control said memberV responsive to manual pressure of an operatorY and the circuit controlling device, and means associated `With a car door for co-ntrolling another of' said circuits,Y said circuit being Ycompleted on movement of the Vcar door to the open position.

13. In a safety car control equipmentjthe combination With a brake cylindenlmanually Ycon-f,VV

trolled means for effecting a supply of iluid un?A der pressure to and release of fluid under pressure toY from the brake cylinder, a manually operated valve device for supplying fluid under pressure to and releasingrfluid under pressure from said' pipe, valve means controlled by brakeY cylinder pressure for controlling communication fromsaid valve device to said emergency valve device and` operatedupon a predetermined increase in brake cylinder pressure for closing-said communication,

and a one-Way communication by-passing said valve means for supplying fluid under pressure from said valve device to said'emergency valve device. Y

y JOI-INF. CRAIG, 

